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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 38 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P1490: Vacuum Cut Valve By-Pass Valve Circuit >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Maxima and 2002 Infiniti I35. However, it is still accessible from the selected car via links, so may be relevant.
  1. If using CONSULT-II, go to next step. If using generic scan tool, go to step  3 .
  2. Turn ignition off and on. Select VC/V BYPASS/V in ACTIVE TEST mode with CONSULT-II. Press ON/OFF on CONSULT-II screen. Clicking noise should be heard from vacuum cut valve by-pass valve. For location, see Figure . If clicking noise is heard, go to step  8 . If clicking noise is not heard, go to next step.
  3. Turn ignition off. Disconnect vacuum cut valve by-pass valve harness connector. See Figure . Turn ignition on. Measure voltage between ground and vacuum cut valve by-pass valve harness connector terminal No. 1 (Red/Yellow wire). If battery voltage exists, go to step  5 . If battery voltage does not exist, go to next step.
  4. Check the following:
    • Check fuse No. 20 (15-amp) located in fuse block under left side of instrument panel.
    • Check for poor connection at fuse block connector M19 terminal 11L (Red/Yellow wire). See Figure .
    • Check for poor connection at White, 16-pin connector M5 terminal No. 2 (Red/Yellow wire). See Figure . Connector M5 is located under left side of instrument panel. See Figure or Figure .
    • Check for open or short between vacuum cut valve by-pass valve and fuse.

    Repair as necessary.

  5. Turn ignition off. Disconnect ECM harness connector. See Figure . Check continuity of Orange/Green wire between vacuum cut valve by-pass valve harness connector terminal No. 2 and ECM harness connector terminal No. 28. See Figure . Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If circuit is okay, go to step  7 .
  6. Check the following:
    • Check for poor connection at White, 18-pin connector M6 terminal No. 10 (Orange/Green wire). See Figure . Connector M6 is located under left side of instrument panel. See Figure or Figure .
    • Check for poor connection at White, 20-pin connector M81 terminal No. 16 (Orange/Green wire). See Figure . Connector M81 is located near ECM. See Figure or Figure .
    • Check for open or short between vacuum cut valve by-pass valve and ECM.

    Repair as necessary.

  7. If using CONSULT-II, go to next step. If using generic scan tool, go to step  9 .
  8. Reconnect all harness connectors. Turn ignition on. Perform VC/V BYPASS/V in ACTIVE TEST mode with CONSULT-II. When VC/V BYPASS/V is ON, air should flow through vacuum cut valve by-pass valve. When VC/V BYPASS/V is OFF, air should not flow through vacuum cut valve by-pass valve. Valve should switch in less than one second. If operation is as specified, go to step  10 . If operation is not as specified, replace vacuum cut valve by-pass valve.
  9. Remove vacuum cut valve by-pass valve. Using jumper wires, apply battery voltage to valve terminals. See Fig 1 . Air should flow between ports "A" and "B". Remove jumper wires. Air should not flow. Valve should switch in less than one second. If operation is as specified, go to next step. If operation is not as specified, replace vacuum cut valve by-pass valve.
  10. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Testing Vacuum Cut Valve By-Pass Valve
G97H06109Courtesy of NISSAN MOTOR CO., U.S.A.
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